The present invention relates generally to railway tank car components, and more particularly to a siphon drainpipe system and method for a railway tank car.
Railway tank cars are the primary means of bulk transportation of liquids in North America, and constitute about one-seventh of the North American railcar fleet. In the United States, Canada, and Mexico, 220,000 railway tank cars carry over three million shipments annually. Although tank cars are usually associated with the movement of hazardous materials, half of these shipments are non-regulated food and industrial products.
Many railway tank cars are configured for top and/or bottom loading and/or unloading. In many instances, a siphon pipe is attached to a nozzle of the railcar at an upper portion thereof. The siphon pipe may be used to load and/or unload lading. In order to achieve optimum performance during loading and unloading, the configuration of the siphon pipe and associated components must be manufactured, installed, and operated according to stringent specifications. During operation of the railway tank car, many such components are subject to damage, wear, and other problems that may affect the performance of the railway tank car and the loading/unloading system(s).
The present invention includes a siphon drainpipe system and method for use in a railway tank car that substantially eliminates or reduces disadvantages or problems associated with previously developed systems and methods. In particular, the present invention contemplates a siphon pipe having a generally flexible portion coupled with a generally rigid portion. The flexibility provided by the flexible portion prevents damage to components of the railway tank car during operation. Furthermore, the flexible portion simplifies the design, manufacture, installation, and operation of the railway tank car and the associated siphon drainpipe system.
In accordance with a particular embodiment of the present invention, a railway tank car includes a tank at least partially defined by a generally elongate hollow cylinder having closed ends. The tank includes an upper surface and a lower surface, and forms a generally enclosed interior portion. A nozzle is coupled with the upper surface of the tank, and may be coupled with a siphon pipe which extends from the nozzle toward the lower surface of the tank. The siphon pipe is at least partially disposed within the interior portion of the tank. In accordance with a particular embodiment, the siphon pipe includes a generally rigid, metallic portion disposed adjacent the upper surface of the tank, and a generally flexible portion disposed adjacent the lower surface of the tank.
In accordance with another embodiment of the present invention, the generally flexible portion of the siphon pipe comprises convoluted tubing. The generally flexible portion may include a cuffed portion configured to be coupled with the generally rigid portion. A compression band may be disposed about an exterior portion of the cuffed region. The compression band is operable to couple the generally flexible portion and the generally rigid portion. The generally rigid portion may include a recessed region being configured to receive the cuffed region of the flexible portion.
In accordance with yet another embodiment of the present invention, a method for installing a siphon drainpipe system within a tank of a railway tank car is provided. The tank is at least partially defined by a generally elongate hollow cylinder having closed ends. The tank includes an upper surface and a lower surface, and forms a generally enclosed interior portion of the tank car. The method includes coupling a siphon pipe with a nozzle coupled with the upper surface of the tank. The siphon pipe is at least partially disposed within the interior portion of the tank. In accordance with a particular embodiment, the siphon pipe includes a generally rigid, metallic portion disposed adjacent the upper surface, and a generally flexible portion disposed adjacent the lower surface of the tank.
Technical advantages of the present invention include a siphon pipe system and method for use in a railway tank car which substantially reduces or eliminates problems caused by contact between railcar tank components during operation. Many factors may lead to the deformation of the tank, or its associated components, during use. For example, loading, unloading, car movement, braking, coupling of railcars, impact with objects, and many other factors lead to the deformation of the tank and/or contact between components of the railway tank car. The generally flexible portion of the siphon pipe allows such contact to occur without damage, since the flexible portion will deform before causing damage to itself or adjacent components. This reduces the amount of repair, retrofit, and/or replacement of siphon pipe and associated components that are necessary due to such problems. Furthermore, this substantially eliminates environmental contamination experienced when such problems cause a breach of the railway tank car enclosure and allow the lading to be exposed to ambient environment.
Another technical advantage of the present invention includes a siphon pipe system and method for use in a railway tank car which may be modified and/or retrofit after installation in the car. Certain clearances are required for the proper operation of the railway tank car and associated siphon pipe system. The flexible portion of the siphon pipe of the present invention may be modified and/or trimmed in place. This prevents engineering and manufacturing errors which may occur in prefabricated systems. For example, the flexible portion of the siphon pipe may be installed in the railway tank car after other components have been installed. This allows the installer and/or operator to maintain precise tolerances between the siphon pipe and adjacent railway tank car components. Accordingly, configuration of the siphon pipe and operation of the railway tank car and siphon pipe system may be optimized.
Other technical advantages will be readily apparent to one skilled in the art from the following figures, descriptions and claims. Moreover, while specific advantages have been enumerated above, various embodiments may include all, some or none of the enumerated advantages.